Position Of Genital Pore Research Articles

Redescription of Proteocephalus bagri and p. Rhamdiae (Cestoda: Proteocephalidae), parasites of Rhamdia quelen (Siluriformes: Pimelodidae) from South America, with comments on morphological variation.

The pimelodid fish Rhamdia quelen (Quoy et Gaimard, 1824) in South America harbours two species of proteocephalid cestodes, Proteocephalus bagri Holcman-Spector et Mañé-Garzón, 1988 and P. rhamdiae Holcman-Spector et Mañé-Garzón, 1988. These species are redescribed based on a detailed morphological study, supported by multivariate analysis (principal component analysis). Features distinguishing these species are: (1) the shape of proglottides, (2) the mean number of testes, (3) the topography of vitelline follicles, (4) the thickness of internal longitudinal musculature, (5) the mean number of uterine branches, (6) the ratio of cirrus pouch length to proglottis width, (7) the shape of ovary in mature and gravid proglottides and (8) the genital pore position in mature proglottides. The specific status of P. bagri and P. rhamdiae is confirmed and neotypes of both species are designated.

Two new species of Macrobothridium (Cestoda: Diphyllidea) from rhinobatid elasmobranchs in the Gulf of Gabès, Tunisia, with notes on the status of the genus.

As a result of an investigation of metazoan parasites of elasmobranch fishes in the Gulf of Gabès, Tunisia, we discovered 2 new species of diphyllidean cestodes. Macrobothridium euterpes n. sp. is described from the spiral intestine of Rhinobatos rhinobatos, and Macrobothridium syrtensis n. sp. from the spiral intestine of Rhinobatos cemiculus. Macrobothridium euterpes is distinguished from the only other species in the genus (Macrobothridium rhynchobati) by the number of rostellar hooks, size, genital pore position, vagina position, and ovary shape. Macrobothridium syrtensis is distinguished from M. rhynchobati by the hook morphology, testis number, and overall size, and from M. euterpes by the number of rostellar hooks, testis number, genital pore position, vagina position, and ovary shape. These are the first 2 species added to the genus since its establishment in 1989. A standardized formula for representing the number and arrangement of rostellar hooks in diphyllidean species is presented.

Four new species of Acanthobothrium (Cestoda: Tetraphyllidea) from the whiptail stingray Dasyatis brevis in the Gulf of California, Mexico.

Examination of the spiral intestines of 29 whiptail stingrays, Dasyatis brevis, from 6 sites in the Gulf of California, Mexico in 1993 and 1996 resulted in the discovery of 4 new species of Acanthobothrium: Acanthobothrium bullardi, Acanthobothrium dasi, Acanthobothrium rajivi, and Acanthobothrium soberoni. This brings the total number of species of Acanthobothrium known from the eastern Pacific Ocean to 34. With 22 additional species reported from elasmobranchs from the western Atlantic Ocean, and over 100 species globally, the number of interspecific comparisons required to justify the designation of a new species is rather unwieldy. To facilitate these and future comparisons, and in the absence of a phylogenetic hypothesis for this genus, the 56 species of Acanthobothrium from these 2 geographic regions were categorized for 4 characters: total length (< or = or > 15 mm), number of segments (< or = or > 50 segments), number of testes (< or = or > 80), and symmetry of poral and aporal ovarian lobes. These 56 taxa and their categories are presented in tabular form. Based on these characters, A. bullardi, A. dasi, and A. rajivi are category 2 species (they are relatively small, possess few segments, relatively few testes, and exhibit asymmetrical ovaries); A. soberoni is a category 6 species (it is a relatively longer worm with a larger number of segments, but with fewer testes and an asymmetrical ovary). All 4 species differ from 1 another and from species in other geographic regions in further subtleties of these 4 characters as well as hook size and relative length of hook prongs, cirrus sac size, genital pore position, number of columns of testes anterior to the cirrus sac, and number of postvaginal testes. Five specimens that appear to represent a new species of Acanthobothroides were also collected. This species is figured and some details of the morphology are described, but the material was considered to be insufficient to allow for formal description of this species at this time. This is the first record of either of these genera of onchobothriid tapeworms from the Gulf of California.

Paranoplocephala maseri n. sp. (Cestoda, Anoplocephalidae), a parasite of sagebrush voles Lemmiscus curtatus (Rodentia) in the USA.

Paranoplocephala maseri n. sp. is described from Lemmiscus curtatus (Cope) in the USA. The new species is related to Paranoplocephala omphalodes (Hermann, 1783), P. caucasica (Kirschenblat, 1938), P. kirbyi Voge 1948, P. microti (Hansen, 1947) and P. macrocephala (Douthitt, 1915) sensu Genov et al. (1996). P. maseri n. sp. differs from P. omphalodes in the position of the genital pores, testes and cirrus-sac; from P. caucasica, in which there is an unarmed cirrus, in both the distribution and larger number of testes; from P. kirbyi in the distribution of the testes, the position of the genital pores and egg dimensions; from P. microti in the distribution and smaller number of testes, the smaller egg dimensions and the position of the genital pores; and from P. macrocephala in the position of genital pores and cirrus-sac.

Paramphistome digeneans from shape Xenopus species (Pipidae) in Africa: taxonomy, host-specificity and biogeography

The taxonomy, host range and geographical distribution of paramphistome digeneans from Xenopus spp. in sub-Saharan Africa are reviewed. Two representatives of Progonimodiscus Vercammen-Grandjean, 1960 are recognised, both of which are narrowly or primarily specific to Xenopus. An analysis of morphometric and meristic characters indicated geographical variation in Progonimodiscus doyeri (Ortlepp, 1926), with two allopatric forms showing significant, but continuous, variation in testis size and vitelline follicle number. P. colubrifer n. sp. is distinguished from P. doyeri by the form of muscular elevations on the acetabulum accessory peduncle. It infects Xenopus ( Silurana) tropicalis-like toads from lowland tropical rain forest zones in Nigeria, Togo and the Ivory Coast, while P. doyeri occurs in hosts of the subgenus Xenopus from a wide variety of biotypes. Previous literature records indicate the presence of the southern P. doyeri morphological variant in X. laevis laevis in South Africa and Zimbabwe and the northern variant in X. l. victorianus, X. fraseri aff. and X. muelleri in the Democratic Republic of Congo, X. wittei in Uganda and the Democratic Republic of Congo, and the ranid Conraua crassipes in Cameroon (the only record of Progonimodiscus from a non-pipid host). New host and/or geographical records for this species are of the northern form in X. l. victorianus, X. l. bunyoniensis and X. vestitus in Uganda, X. l. sudanensis in Cameroon, X. borealis in Kenya, X. pygmaeus in the Democratic Republic of Congo, X. fraseri aff. in Cameroon, X. wittei aff. in the Democratic Republic of Congo and X. muelleri in Cameroon and Nigeria. While the geographical limits of the two P. doyeri variants are not known with precision, existing data are consistent with a “turnover” in the region of 15°S, where a notable discontinuity occurs in the distributions of other Xenopus parasites. Species of Diplodiscus Diesing, 1836 in Xenopus hosts are rare. Diplodiscus peregrinator n. sp. was recovered from X. tropicalis at a single locality in the Ivory Coast and distinguished by a combination of body size, egg size, genital pore position and acetabulum morphology. D. fischthalicus Meskal, 1970 was not found during the present study.

Systematic Resolution of Crossobothrium Linton, 1889, and Taxonomic Information on Four Species Allocated to That Genus

The systematic status of the tetraphyllidean genus Crossobothrium is resolved. The description of the type species Crossobothrium laciniatum is emended to include new information from light and electron microscopy. Orygmatobothrium dohrnii is transferred to Crossobothrium and its description is emended. Crossobothrium dohrnii n. comb. differs from C. laciniatum in the morphology of large microtriches on the distal bothridial surface, the presence of irregular papillose projections on the distal bothridial surface, the possession of irregular, incomplete loculi on the bothridial margin morphology, and exhibiting oblong testes. The genital pore position of C. dohrnii also differs from C. laciniatum. Species of Crossobothrium differ from species in other sampled tetraphyllidean genera in apical sucker tegumentary surface morphology. The 2 species differ from species in all tetraphyllidean genera in possessing a field of deep longitudinal muscles and a greater number of follicles in the vitelline field at the level of the ovary. Two species formerly allocated to Crossobothrium, Phyllobothrium filiforme, and Phyllobothrium triacis, are transferred to Paraorygmatobothrium, and their descriptions are emended. Three other species previously allocated to Crossobothrium, namely Orygmatobothrium angustum, Phyllobothrium squali, and Tetrabothrius longicolle, are considered incertae sedis. As a taxonomic entity, Crossobothrium has suffered from a case of mistaken identity with tetraphyllidean species consistent in morphology with the genus Paraorygmatobothrium.

A revision of Oncomegas Dollfus, 1929 (Cestoda: Trypanorhyncha: Eutetrarhynchidae), the description of two new species and comments on its classification

Oncomegas Dollfus, 1929 is completely defined for the first time based upon a redescription of the type-species, O. wageneri (Linton, 1890) from Dasyatis centroura (Mitchill), and the description of two new species, O. paulinae from Urolophus halleri Cooper and O. australiensis from Aetobatus narinari (Euphrasen). The three species of Oncomegas are differentiated from one another by scolex ratio, basal and metabasal armatures, testis number and arrangement, number of vaginal sphincters, form of gravid uterus, position of genital pores, and form of the osmoregulatory canals. Diagnostic characters of Oncomegas are: acraspedote scolex, two bothridia, asymmetrical tentacular basal swelling, basal armature with macrohook, typical heteroacanthous metabasal armature, prebulbar organs, elongate bulbs, retractor muscle origin at base of bulb, external seminal vesicle present, testes in two longitudinal rows or bands, seminal receptacle, lack of a postovarian testicular space, linear gravid uterus with lateral diverticula, and osmoregulatory ducts dorsal to cirrus-sac. The combination of heteroacanthous typical tentacle armature, two bothridia lacking ciliated pits, presence of prebulbar organs, retractor muscles originating at base of bulbs and posterior ovary warrant the placement of Oncomegas in the Eutetrarhynchidae. Oncomegas is most similar to Eutetrarhynchus Pintner, 1913 in arrangement of hooks of principal rows in opposing half-spirals which abut in ‘V’-formations on both internal and external faces, presence of a basal armature and swelling, presence of an external seminal vesicle, testes confined to the intervascular medullary zone, posterior ovary and circumcortical vitelline field. Oncomegas differs from all eutetrarhynchid genera in the possession of a single macrohook in the basal armature and all except Eutetrarhynchus in the lack of a wide space between hook files 1 and (1′) of the principal rows.

Revision and phylogenetic analysis of the North American species of Telorchis Luehe, 1899 (Cercomeria: Trematoda: Digenea: Telorchiidae)

Telorchiids are plagiorchiform digeneans inhabiting the intestines of freshwater turtles, snakes, and salamanders. Previous systematic revisions of the group have been problematical because of a lack of information on intraspecific morphological variation. In the present study, examination of substantial numbers of specimens leads to the conclusion that 11 of the 31 nominal species of Telorchis reported from North America are valid. Numerical phylogenetic systematic analysis based on 18 homologous series and 30 total characters resulted in a single tree with a consistency index of 94%, due to two homoplasious characters. To maintain a classification consistent with the phylogenetic tree that is also most similar to previous nomenclature, only one of four previously proposed genera is recognized. The two relatively most plesiomorphic species are found in salamanders, whereas the rest inhabit amniotes (specifically turtles and snakes). Five of the nine species inhabiting amniotes appear to have co-speciated with their hosts. Two of the remaining four species appear to have evolved sympatrically via host switching from turtles to snakes. The remaining two species appear to have evolved sympatrically and without host switching, facilitated by mechanical premating isolation due to the appearance of an apomorphic genital pore position. Using the number of host species inhabited as an index of host specificity, it appears that the more recently evolved the species of Telorchis, the fewer hosts it inhabits.

Geographic and Host-Related Variation among Species of Fessisentis (Acanthocephala) and Confirmation of the Fessisentis fessus Life Cycle

Specimens of the 4 known species of Fessisentis, acquired through new collections in 6 states and laboratory infections, were compared with existing descriptions and collections. It was concluded that the number od longitudinal rows of proboscis hooks and lengths of proboscis receptacles, largest proboscis hooks, and reproductive systems are not useful in distinguishing the species. Egg size is of limited usefulness. Regardless of host or geographical locality, proboscis shape and length, the number of proboscis hooks in each longitudinal row, hook shape and size distribution, number of testes, number of cement glands, and female genital pore position are consistent differences. Cystacanths of Fessisentis fessus occurred in aquatic isopods, Asellus forbesi and Lirceus lineatus, in Jackson County, Illinois, where Siren intermedia is the usual definitive host. Laboratory infections confirmed the life cycle of this species.

Studies On Cestodes of the Common Indian Mynahs Acridotheres Tristis and a. Ginginianus (Aves)

A comprehensive study of the cestodes of two common birds, viz., Acridotheres tristis (Linnaeus) and A. ginginianus (Latham) have been made. These birds, frequenting the outskirts of the city of Lucknow, have been found being parasitized by only three species of cestodes: two hymenolepids, viz., Hymenolepis farciminosa (Goeze, 1872) and H. magna Singh, 1952 and one dilepid cestode, viz., Choanotaenia acridotheresi sp. nov. The present study adds important data to the morphology of the hymenolepids. A detailed description of these three species including the components of the so-called egg-shell and gross morphology of the contained hexacanth is given. One notable observation made concerns the occurrence of penetration glands in the hexacanths of these cestodes. C. acridotheresi is chiefly characterized by a double row of rostellar hooks, craspedote proglottides, size of proglottides and of other structures, number of testes and position of genital pore. This work also includes a discussion on the systematic position of Monopylidium chandleri Moghe, 1925. This species has been removed from Panuwa Burt, 1940 and reinstated to the genus Choanotaenia Railliet, 1896.

Echinococcus oligarthrus (Diesing, 1863) from a Panamanian Jaguar (Felis onca L.)

FIGURES 1, 2. Echinococcus oligarthrus from a Panamanian jaguar. 1. Maturing proglottid showing position of genital pore and cirrus sac X 100. 2. Hooks from scolex; two large and one small X 500. redescribed the species on the basis of a collection from a jaguarundi (Felis yagouaroundi Geoffroy) that had died at the London Zoo. Recently Thatcher and Sousa (1966, Ann. Trop. Med. Parasit. 60: 405-416) presented a redescription of E. oligarthrus based on Panamanian material from both the previously known felid definitive hosts, and implicated man as a possible intermediate host. The present report supplements the previous paper in that it records E. oligarthrus from the jaguar (Felis onca L.) for the first time. In February 1967, a 75-lb female jaguar was shot near Achiote, Colon Province, Republic of Panama. Examinations of the upper intestinal tract revealed the presence of about 6,000 specimens of Echinococcus. The parasites occurred throughout the small intestine, but were more concentrated in the anterior portion. The worms showed development of the reproductive structures, but they were not gravid. That the worms belong to the species E. oligarthrus is shown by the limited number of testes and the anterior position of the genital pore (Fig. 1). The hook morphology is typical of young specimens of E. oligarthrus. Although the small hooks are almost completely developed, the large hooks lack well-developed handles (Fig. 2). The jaguar was obtained in an area of Panama that Thatcher and Sousa (loc. cit.) had reported to be endemic for E. oligarthrus. To date, infections have been found in four wild felids (two pumas, one jaguarundi, and one jaguar) from the Achiote area. Two young jaguars from the same area were negative.